How to choose plastic additives

The choice of additive type is determined based on the type of plastic and the degree of aging.

New polyolefin materials generally only add a small amount of auxiliaries such as antioxidants, UV absorbers, etc. during processing and molding. When the waste is regenerated, generally only a small amount of colorant can be added, so the formulation is not difficult to determine. Unless such plastics age severely and become hard and brittle, the composition of the ingredients needs to be determined on a case-by-case basis.

The composition of PVC plastics is relatively complex, especially soft polyvinyl chloride, which contains more types of additives, including plasticizers, stabilizers, UV absorbers, lubricants, and pigments, among which plasticizers are mainly used. , The maximum amount. Its products are affected by weather conditions such as light and heat in the course of use, plasticizers gradually seep out, and the products harden, especially their physical properties are greatly reduced, gradually aging, and can not meet the use requirements and become waste products. The use of these waste products must be supplemented with sufficient amounts of plasticizers and other auxiliaries to maximize the restoration of its mechanical properties. Therefore, it is important to determine the formula reasonably.

The amount of plasticizer added is mainly determined by the required hardness of the reclaimed PVC products. Therefore, the ratio of hard and soft PVC recycled products should be considered. The residual amounts of plasticizers in soft products such as polyvinyl chloride films, artificial leather, and wallpapers are not the same as those in rigid pipes and profiles. Therefore, as long as the hard and soft recycled materials are blended with each other, adjustments are made. The blending ratio of the two can produce remanufactured products with required hardness, can reduce the amount of plasticizers, and even do not use plasticizers.

The general principle of the selection of additives in the furnish is to ensure that the recycled products have a certain performance, meet the requirements of use, without excessive costs. In general, the following points need to be considered:

(1) Because of the low price of waste plastics and recycled products, the prices of the additives used are also cheaper.

(2) Because waste plastics are often mixtures of various color wastes, dark colorants are generally added during reprocessing, so the appearance color of the selected additives is not high.

(3) Additives should be able to meet certain performance requirements of recycled products.